Defensive Responses of Neotropical Harvestmen (Arachnida, Opiliones) to Generalist Invertebrate Predators

Cook, Dayna R.; Smith, Adam T.; Proud, Daniel N.; Víquez, Carlos; Townsend, Victor R.

doi:10.18475/cjos.v47i3.a20

Cited by 11 publications

(8 citation statements)

References 24 publications

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“…An unpredictable escape trajectory, such as that observed during bobbing, can increase evasion of predators, as suggested for desert rodents (Moore et al, 2017). A behaviour similar to bobbing has been observed previously in harvestmen (Holmberg et al, 1984;Cockerill, 1988;Wade et al, 2011;Cook et al, 2013), although these descriptions did not involve forward body displacement. In contrast to running, stotting and bobbing gaits, walking is unlikely to function as an escape manoeuvre given that walking harvestmen had lower speed and acceleration and a less sinuous trajectory compared with the other gaits.…”

Section: Adaptive Value Of Gaitssupporting

confidence: 56%

Variation in movement: multiple locomotor gaits in Neotropical harvestmen

Escalante

Badger

Elias

2019

Biological Journal of the Linnean Society

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In order to move successfully in variable conditions, many animals have evolved the ability to switch between several patterns of locomotion or gaits. Here, we describe and differentiate between putative locomotor gaits in the harvestman, an arachnid that uses a hexapod-like alternate tripod gait. We recorded Neotropical harvestmen of the genus Prionostemma moving across a flat surface using high-speed video. We reconstructed three-dimensional trajectories and associated kinematics and found four different locomotor gaits: running, stotting, bobbing and walking. Gaits differed in their performance and postural kinematics, body trajectory, gait diagrams and/or kinetic and potential energy exchange. Our approach points out the importance of using multiple kinematic features to differentiate gaits. The use of a specific gait was not predicted by leg length, body area or sex. We propose testable hypotheses regarding the function of each gait and the factors that drive the evolution of different gaits. Ultimately, the diversity of locomotory gaits can allow animals to respond to different environmental challenges and contexts.

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Section: Adaptive Value Of Gaitssupporting

confidence: 56%

Variation in movement: multiple locomotor gaits in Neotropical harvestmen

Escalante

Badger

Elias

2019

Biological Journal of the Linnean Society

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“…We found at least one article for all the branches of the cladogram. Two articles were selected for Arachnida, 31 , 32 Hexapoda, 29 , 33 Crustacea, 34 , 35 Chondrichthyes, 36 , 37 Actinopterygii, 38 , 39 Amphibia, 40 , 41 Bifurcata, 21 , 42 Metatheria, 17 , 43 Artiodactyla, 44 , 45 Canidae, 46 , 47 Rodentia, 23 , 48 Leporidae, 49 , 50 Cercopithecoidea 51 , 52 and Homo sapiens . 25 , 26 Three articles were selected for the Aves class.…”

Section: Resultsmentioning

confidence: 99%

The evolutionary origin of near-death experiences: a systematic investigation

Peinkhofer

Martial

Cassol

et al. 2021

Brain Communications

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Near-death experiences are known from all parts of the world, various times and numerous cultural backgrounds. This universality suggests that near-death experiences may have a biological origin and purpose. Adhering to a preregistered protocol, we investigate the hypothesis that thanatosis aka. death-feigning, a last-resort defense mechanism in animals, is the evolutionary origin of near-death experiences. We first show that thanatosis is a highly preserved survival strategy occurring at all major nodes in a cladogram ranging from insects to humans. We then show that humans under attack by animal, human and “modern” predators can experience both thanatosis and near-death experiences, and we further show that the phenomenology and the effects of the two overlap. In summary, we build a line of evidence suggesting that thanatosis is the evolutionary foundation of near-death experiences and that their shared biological purpose is the benefit of survival. We propose that the acquisition of language enabled humans to transform these events from relatively stereotyped death-feigning under predatory attacks into the rich perceptions that form near-death experiences and extend to non-predatory situations.

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“…Among the three cosmetid species that we examined, only Cynorta marginalis exhibited a high rate of injury to leg I (similar to legs II and IV). However, leg dabbing behavior has not been reported in this species (Wade et al, ; Smith et al, ; Cook et al, ). Willemart et al () discussed the significance of leg I as a sensory appendage and noted several significant similarities in the distribution of cuticular structures on Legs I and II.…”

Section: Discussionmentioning

confidence: 92%

“…Surprisingly, there are relatively few direct observations of loss or injuries to the legs of harvestmen. In the lab, Cook et al () observed one instance of autospasy by an adult Prionostemma sp. (Eupnoi: Sclerosomatidae) in an encounter with ctenid spider.…”

Section: Discussionmentioning

confidence: 99%

Leg injuries and wound repair among cosmetid harvestmen (Arachnida, Opiliones, Laniatores)

Townsend

Schaus

Zvonareva

et al. 2016

Journal of Morphology

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Previous studies of leg injuries in harvestmen have focused on the fitness consequences for individuals that use autospasy (voluntary detachment of the leg) as a secondary defense mechanism. Leg damage among non-autotomizing species of laniatorean harvestmen has not been investigated. Under laboratory conditions, we damaged femur IV of Cynorta marginalis and observed with scanning electron microscopy (SEM) the changes in these wounds over ten days. We also used SEM to examine leg damage from individuals of three species of cosmetid harvestmen that were collected in the field. On the basis of changes in the external surface of the hemolymph coagulum, we classified these wounds as fresh (coagulum forming), recent (coagulum with smooth surface), older (coagulum is scale-like with visible cell fragments), and fully healed (scale replaced by new cuticle growth on the terminal stump). Our observations indicate that wound healing in harvestmen occurs in a manner comparable to that of other chelicerates. Leg injuries exhibited interspecific variation with respect to the overall frequency of leg wounds and the specific legs that were most commonly damaged. In addition, we measured walking and climbing speeds of adult C. marginalis and found that individuals with fresh injuries (lab-induced) to femur IV walked at speeds significantly slower than uninjured adults or individuals collected from the field that had fully healed wounds to a single leg. J. Morphol. 278:73-88, 2017. ©© 2016 Wiley Periodicals,Inc.

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Defensive Responses of Neotropical Harvestmen (Arachnida, Opiliones) to Generalist Invertebrate Predators

Cited by 11 publications

References 24 publications

Variation in movement: multiple locomotor gaits in Neotropical harvestmen

Variation in movement: multiple locomotor gaits in Neotropical harvestmen

The evolutionary origin of near-death experiences: a systematic investigation

Leg injuries and wound repair among cosmetid harvestmen (Arachnida, Opiliones, Laniatores)

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